Cards are not expensive things now compared to the rest of the investment you have tied up in your equipment. I tend to treat them as consumable, just like film was back in the old days.

I always shoot in RAW DNG and use SanDisk Extreme series cards, which have never ever caused me any problems and are always bought from reliable sources to ensure they're "real deal". For safety again I tend to stick to small 8GB cards, for the fatal "eggs in basket" syndrome.

If your images are important to you like mine are to me, a quick thought on card back ups. I use an "Ingestion" backup work flow, i.e. always copy the images to your backup first and then copy from this to the primary location, By doing this, a single visual check of the images on the primary version will validate both the primary and the backup. For more security you could then copy images from primary to a second backup. This may sound a bit heavy handed, but I would suggest it as best practice method.

I change cards relatively often even when they are working fine, just based on their usage and time owned. For me it's really a "no brainer" as I can't have any failures on my watch.

Heh, going into the bush for a week you'll need more than one or two cards I like to travel light, so I don't bring a laptop or any such thing.

When a card is full (or close enough) I flip the read-only switch so it's easy to sort them out should my cards get mixed up.

When I get home the images are copied to the primary drive, then mirrored to an online backup service. I also do periodic backups to portable disks which I store away from home. Then I can format the cards.

2 cards, and the 2nd never gets any action, it's just a backup. I cannot imagine a situation where i'd overflow onto the 2nd card. Who are you people?!

I shoot all-day music festivals with two K-5 bodies, and a K-01 as a video camera/backup body. I can take 3000 shots in a day. Each camera has a 32 gB card. The fourth card (8 gB) lives in the battery grip of one of the K-5's as an emergency backup.
If I only shot lanscapes (and I have enormous respect for your work Mike) I would think like you too.

I have 4 cards. A 2gb from my gone now P&S, heaven forbid Nikon, Then I bought a 4gb for my first Pentax DSLR, the K100D, realizing I it was too small and bought an 8GB. Recently got a deal on a 16GB to use with my K-X. Wanting to shoot some video of a coming up family reunion. And I don't believe I ever filled any of those cards and I shoot only RAW. But I don't see any need to go higher than 16GB on the same consensus as others, if I lost it or it broke, I'd be sad to lose that many photos.

I have one primary card I use day to day. I have two backup cards I don't actively use, but are available if needed, though I've never come close to filling my 8Gb card before I can move pictures to my computer, even if it only runs about 380 DNGs. I don't shoot a whole lot, I guess. Spares are another 8 gig card, and an older 4 gig I used in my P&S. My main 8 is a sandisk extremepro UHS1 card, the other 8 gig is a sandisk class 10, and the 4 is a sandisk class 6.

I shoot all-day music festivals with two K-5 bodies, and a K-01 as a video camera/backup body. I can take 3000 shots in a day. Each camera has a 32 gB card. The fourth card (8 gB) lives in the battery grip of one of the K-5's as an emergency backup.
If I only shot lanscapes (and I have enormous respect for your work Mike) I would think like you too.

i was being a little naive, knowing full well that for sports and event and video shooting, it is very easy to max out a big card. As I've pretty much fallen in as a landscape photographer, I am finding I may go out on a half day hike and am quite pleased if i get three strong keepers. Lots of prep, travel, scouting, then waiting for the light, a brief few minutes of shooting, then pack and go home. These days, I really aim to just get one photo from every outing, yes, plenty of trial shots, outtakes and such, but just one frame up.

2 cards, and the 2nd never gets any action, it's just a backup. I cannot imagine a situation where i'd overflow onto the 2nd card. Who are you people?!

LOL, well, I can't speak for anyone else but I take a lot of pics when I get down to it. I'm doing 2-3 professional shoots a month now plus I have my own projects I do. 300-500 shots per shoot is not uncommon for me and no, I'm not talking about just holding up a camera, clicking away and just praying for the best. I studied my arse off for several years to get a bit better at it than that. I'd like to hope my teachers did a pretty good job of it and that I'm decent at what I do. I'm not a seasoned pro yet but I'm still doing okay and getting better with every shoot, I hope.

About 75-80% of my shots are decent, actually in focus and could justifiably be kept but I am extremely picky when it comes to my client work. I tend to weed out the just okay stuff in favor of the few shots that I think are really good. I don't necessarily keep things just because they are technically competent. They have to be better than that, have some jazz. But I probably actually keep about 60% of what I shoot when it's all said and done. My retention rate went way up the past year or so during my internship. I used to keep maybe 30% if that.

I guess I tend to shoot for about two to three hours at a time unless I'm taking a few quick snaps of product for the web or something. 300-500 pics is really not that much for that period of time when you get to thinking about it and if you're shooting RAW it does take a fair bit of space. I won't shoot jpeg for clients. I shoot RAW at the highest quality setting my K-x has so I will generally use up a couple of 8GBs cards most of the time. The other day I was shooting for about that and I only used the 16GB and I think I filled it up about 3/4 of the way.

It really just depends upon what you're shooting and for how long I guess. On my own I'd probably be okay with 1 of the 8GB cards but when I'm shooting a portrait session I tend to use another one or at least part of one. I take as many shots as the client can comfortably sit for in 2 hours. In that scenario I'd much rather have too many shots to choose from than too few. I really hate having to redo portrait shoots because I didn't do a decent job of it and get enough shots for the package.

If I can't come up with at least 15 or 20 really, really good shots of them in different poses et all then I'm not doing a very good job of it. Hopefully when I get done I'll be able to say "Well, we contracted for a dozen but I actually got 25 or 30 shots that were really, really nice. Do you want to see them all?" I don't ever not admit to a client that I got more than we were going for. Potentially selling a second batch of photos is never a bad thing.

I only contract for about a dozen because I figure that's reasonable and they're probably not going to want to pay for more shots than that anyway. But my actual goal is to get maybe 25 so they'll think twice about it and order a second CD after they see how good the first one is. If they don't, they don't. But a lot of the time they will, if not at that moment, after a few weeks when they've thought about it a bit. I never let them see anything that's not really good though. No one sees my bloopers. That's just bad for business.

But yeah, I'm using up a lot more in terms of space on the memory cards these days. I shoot a whole lot more than I used to just because of work. That's actually why I really have to get a second DSLR soon. I'm going to wear out my K-x in another year or so if I keep using it for both my personal shots and my professional ones. Right now I'm lucky if I have one shoot a week but my goal is 3-4 portrait shoots a week plus a few hours of microstock work and I'm going to need at least 2 DSLR bodies to go there. I'll probably get 2 K-30's or maybe a K5 and a K30 eventually. Right now the K-x is fine but I'll need 2 closer to pro bodies eventually and at least twice the memory cards I've got now.

My computer is full because of many photos (7years old computer) so I have been forced to buy many memorycards.. and the result after eight months of my computer filled up, are 13 memorycards and those makes about 100GB..